Femtosecond laser microhole drilling inside a fused silica optical fiber with optical inner surface quality

摘要

We have demonstrated femtosecond laser microhole drilling inside a fused silica optical fiber with optical inner surface quality. An optical quality microhole with a diameter of 3 μm and a length of approximately 35 μm was produced inside an optical fiber of a cladding diameter of 125 μm. The microhole drilling inside an optical fiber was caused as a result of plasma filamentation of focused femtosecond laser irradiation at a wavelength of 400 nm. The size of the microhole was reproduced with a ray trace of the focused laser beam with consideration of self-focusing. The optical quality of the microhole was verified by measuring the transmittance of 94 % of infrared diode emission.